Question

You are studying lipoprotein processing in a strain of mutant mice. You find that these mice synthesize the same apolipoprotein composition contained in lipoproteins made in the liver and the intestines, whereas, in wild-type mice there are 2 different sized apolipoproteins in these same tissues. Examination of the mRNA processing in the mutant mice would most likely show a defect in which of the following processes?A. alternative polyadenylationB. alternative splicingC. differential cappingD. posttranscriptional modification converting a U to a T residueE. RNA editing

Answer 1

Answer: Option E -- RNA Editing

Explanation:

It should be noted that, RNA editing can be defined as a molecular process via which some cells can make discrete changes to specific nucleotide sequences within an mRNA molecule after it has been generated by RNA polymerase. In addition, we have two major types of RNA editing with 1 being a C-to-U change catalyzed by cytidine deaminase that deaminates a cytidine base into a uridine base, e.g C-to-U editing is with the apolipoprotein B gene in humans. ApoB-100 is expressed in the liver and apoB-48 is expressed in the intestines. The B-100 form comprises of a CAA sequence that is edited to UAA, a stop codon, in the intestines.